Self-deploying apparatuses, assemblies, and methods for drag reduction of land vehicles

ABSTRACT

Examples of drag reduction apparatuses and assemblies for land vehicles, and particularly for attachment to a door of a land vehicle operated by a cam lock bar, are described. A drag reduction apparatus may include a plurality of panels foldedly coupled together and automatically deployable into an unfolded configuration. The panels may be coupled to a base panel that is coupled to the door of the land vehicle by a double-hinge mechanism operated by the cam lock bar. The double-hinge mechanism may draw the base panel toward the centerline of the rear of the land vehicle to allow the door to fully open with the drag reduction apparatus attached. The apparatus may be attached to two adjacent doors of a land vehicle and a plurality of panels on one door configured to overlap with a plurality of panels on the adjacent door.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. application Ser. No.14/863,317 filed Sep. 23, 2015, issued as U.S. Pat. No. 9,333,993 on May10, 2016, which is a continuation of PCT Application No.PCT/US2014/044412, filed Jun. 26, 2014, which application claims thebenefit of U.S. Provisional Patent Application No. 61/840,393, filedJun. 27, 2013, the applications and patents of which are incorporatedherein by reference in their entirety for any purpose.

TECHNICAL FIELD

This present disclosure relates to methods and devices for dragreduction of land vehicles, such as trucks, tractor trailers and similarvehicles.

BACKGROUND

The present disclosure relates to drag reduction for land vehicles, suchas trucks, tractor-trailer rigs, buses, recreational vehicles and thelike. Drag generated by a vehicle may be proportional to the surfacearea of the vehicle, and such larger land vehicles may be particularlyconcerned with reducing drag in order to reduce fuel consumption. Whilecertain drag reduction devices for land vehicles are known, devices ofthis kind may have limitations and may not be suited for allapplications. For example, known drag reduction devices are typicallydesigned to attach to the frame of a truck cargo door. As such, the dragreduction device must be pulled to the side of the truck body and/orswung open in order to access the cargo door. This may be cumbersome asit may add extra steps before an operator can reach the cargo. This maybe particularly disadvantageous for freight or other shipping operatorswho may be operating under tight schedules. Alternate and/or improveddevices for drag reduction may be desirable.

SUMMARY OF THE INVENTION

Examples of apparatuses, systems and methods for drag reduction of landvehicles, such as trucks, tractor trailers and similar vehicles, aredescribed, including examples of drag reduction apparatus for attachmentto a roll-up door of a land vehicle. An apparatus according to examplesof the disclosure may include a plurality of panels including a pair oftop panels, a pair of bottom panels, first and second side panels, and aplurality of transition panels connecting the top, bottom, and sidepanels, the plurality of panels may be foldably coupled to allow thepanels to be provided between a folded configuration in which the panelsmay be flat against each other and a deployed configuration in which thepanels may define a cavity therebetween, wherein the pair of top panelsmay be configured to transition between the folded configuration and thedeployed configuration simultaneously and the pair of bottom panels maybe configured to transition between the folded configuration and thedeployed configuration simultaneously, and an attachment mechanismdisposed along an edge of the top, bottom, and side panels which may beconfigured to foldably couple the edges of the panels to a surface of aland vehicle. The apparatus may further include a pair of base panels,wherein the pair of top panels and the first and second side panels maybe hingedly coupled to the pair of base panels around a perimeter of thecavity, and the bottom panels may be hingedly coupled to the pair ofbase panels midway along a length of the base panels, wherein the panelsare flat against each other against a front surface of the base panelsin the folded configuration. The base panels may include attachmentmechanisms disposed on back surfaces of the base panels opposite thefront surfaces of the base panels, the attachment mechanisms may beconfigured to hingedly attach the base panels to the surface. Theattachment mechanisms may be configured to draw the base panels toward acenterline of the surface when activated. The attachment mechanisms maybe activated by rotating a bar that may be coupled to the attachmentmechanisms.

An apparatus for reducing drag according to examples of the disclosuremay include a first and a second top panel, a first and a second bottompanel, a first and a second side panel, a first plurality of transitionpanels that may connect the first top, bottom, and side panels, thefirst plurality of panels may be foldably coupled, a second plurality oftransition panels may connect the second top, bottom, and side panels,the second plurality of panels may be foldably coupled, wherein thefirst and second plurality of panels may allow the panels to be providedbetween a folded configuration in which the panels may be flat againsteach other and a deployed configuration in which the panels may define acavity therebetween, a first attachment mechanism disposed along an edgeof the first top, bottom, and side panels which may be configured tofoldably couple the edges of the panels to a first base panel, and asecond attachment mechanism disposed along an edge of the second top,bottom, and side panels which may be configured to foldably couple theedges of the panels to a second base panel, wherein the second basepanel may be adjacent to the first base panel, wherein the first andsecond base panels may be configured to be attached to a rear surface ofa land vehicle.

A system for drag reduction according to examples of the disclosure mayinclude a first door and a second door of a land vehicle, the first andsecond doors may each include an edge hingedly coupled to a doorway ofthe land vehicle, wherein the first and second doors may be adjacent,the first and second doors may each include a cam lock bar, and anapparatus that may comprise a plurality of panels, the apparatus may becoupled to the first and second doors, wherein the apparatus may becoupled in a manner configured to allow the first and second doors toopen and close while the apparatus is attached.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several examples in accordance with thedisclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings, in which:

FIG. 1 shows an exemplary apparatus according to the present disclosure,the apparatus shown attached to a door of a truck and in a deployedconfiguration.

FIG. 2 shows an example according to the present disclosure, includingan apparatus attached to a door of a truck, the apparatus shown during afolded or undeployed configuration.

FIG. 3 shows a further example according to the present disclosure,including close-up or partial view of an apparatus attached to a truckdoor and the truck door being operated into an open or partially openposition.

FIG. 4 shows a partial view of an apparatus according to the presentdisclosure as perceived from the bottom looking upward and illustratingan over-center brace member for a top panel of the apparatus.

FIGS. 5A-B show an illustration of a double-hinge attachment methodaccording to examples herein.

FIGS. 6A-C show an example of a double-hinge mechanism according toexamples of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative examples described in the detaileddescription and drawings are not meant to be limiting. Other examplesmay be utilized, and other changes may be made, without departing fromthe spirit or scope of the subject matter presented herein. It will bereadily understood that the aspects of the present disclosure, asgenerally described herein, and illustrated in the Figures, can bearranged, substituted, combined, separated, and designed in a widevariety of different configurations, all of which are implicitlycontemplated.

The present disclosure relates to apparatuses and method for dragreduction of land vehicles. Land vehicles include, but are not limitedto, trucks and tractor trailers. Drag reduction apparatuses according tothe present disclosure may be configured to be self-deploying. Theapparatus may be configured to expand to its unfolded (e.g. deployedstate, for example, as shown in FIG. 1) due to a low pressure regiondeveloping around and/or at the rear end of the vehicle, which may occuras the vehicle increases its speed. Suction or lift force may begenerated and applied to the panels of the apparatus as a result of alower pressure around and/or in the wake of the vehicle as compared toimmediately behind the vehicle. Sufficient lift force to deploy theapparatus may occur when the vehicle reaches a threshold velocity. Insome embodiments, the threshold velocity may be between 35-45 miles perhour. The apparatus may be configured to have a higher or lowerthreshold velocity for deployment. Examples of drag reducing devicesdescribed herein may be referred to as a “ventilated cavity” typedevice, owing to the mechanism of deployment being lift force generatedby a lower pressure region. However, the theory behind the mechanism ofdeployment is provided here by way of explanation, and is not intendedto be limiting.

Apparatuses according to the present disclosure may include a pluralityof rigid or semi-rigid panels which may be foldedly or hingedly coupledtogether, e.g., for allowing the panels to be automatically movedbetween a first (e.g., folded or undeployed) configuration and a second(e.g., unfolded or deployed) configuration on attaining a thresholdspeed of the vehicle to which the apparatus is attached.

FIG. 1 illustrates an example apparatus 100 in the deployedconfiguration according to an embodiment of the disclosure. Theapparatus 100 is illustrated installed on a truck trailer 10 with twoadjacent hingedly attached doors 12A-B. Each door 12A-B includes a camlock 14A-B coupled to a cam bar 16A-B for opening, closing, and securingthe doors 12A-B. The apparatus 100 may be attached to doors havingdifferent configurations than the configuration illustrated in FIG. 1.The apparatus for drag reduction 100 may include a plurality of panels,including a pair of top panels 102A-B, a pair of bottom panels 112A-B,and first and second side panels 106A-B. The first and second sidepanels may also be referred to as driver-side 106A and curb-side 106Bpanels, although it is to be understood that the designation of“driver-side” and “curb-side” may change depending on the configurationof the vehicle and requirements for positioning the driver side to meetlocal laws or regulations. The apparatus may also include a plurality oftransition panels 104A-B, 108A-B connecting the top, bottom and sidepanels. The combined top 102A-B, combined bottom 112A-B and each of theside 106A-B panels may be generally rectangular or slightly trapezoidalin shape. The transition panels 104A-B, 108A-B may be generallytriangular and may be disposed such that they bridge the gaps betweenthe top, bottom, and/or side panels. Other geometries may be possiblewithout departing from the principles of the invention.

The plurality of panels may be folded according to any number of foldingconfigurations. In an example embodiment of the disclosure illustratedin FIG. 2, the top panels 102A-B may fold on top of the side panels106A-B and be the outermost panels when the apparatus 100 is in thefolded configuration. In other embodiments, the side panels 106A-B maybe the top most or outer most panels in the folded configuration, withthe top 102A-B and/or bottom panels 112A-B disposed between the sidepanels 106A-B and the door 12A-B. In the deployed configuration, theapparatus 100 may define a cavity 120 between at the panels. Forexample, as shown in FIG. 1, a generally rectangular or slightly taperedrectangular cavity 120 may be defined between the top 102A-B, bottom112A-B, and at least portions of the side 106A-B panels, which mayprovide aerodynamic advantages as may be appreciated by those skilled inthe art. Depending on the folding configurations, the top 102A-B, bottom112A-B, and/or side 106A-B panels may combine with adjacent transitionpanels 104A-B, 108A-B to form generally rectangular or slightlytrapezoidal panel sections along vertical and horizontal axis whenunfolded to define the cavity 120 therebetween. The panels may be shapedand/or sized so as to achieve a desired shape at the tail end of thevehicle, which may be selected for optimal or improved drag reduction.

The panels may be made of a lightweight material, such as a polymer orcomposite. In some examples, one or more of the panels may be made fromsheet metal, fiber board, or other semi-rigid or rigid structures ormaterials. The panels may be configured such that they maintain theirshape without any substantial flex or sag while in the deployedconfiguration. In some examples, the panels may be formed using a fiberreinforced polypropylene or polyethylene (FRP) material and may have athickness of about 0.05 to about 0.24 inches. The panels may generallyhave any thickness which can be accommodated between the cargo door andthe side of the vehicle when the door is secured/stowed in an openposition (see e.g., FIG. 3). In some examples, the panels may be made offoam which may be laminated on one or both sides. The foam may bepolyethylene foam, and in examples, it may be laminated (e.g. faced)using one or more layers for improved durability of the panels and/orfor preventing damage to the core, such as by preventing intrusion ofpollutants into the foam core. While not meant to be limiting, in someexamples, the outer layers may be made of substantially any polymericmaterial, for example nylon, polyester, mylar, or any other of a varietyof durable polymeric materials. In some examples, the outer layers maybe provided as a film or a woven layer of polymer or aramid fibers.Other materials may be used for the outer layers and/or core. In someexamples, the panels may be mylar or nylon faced foam insulation panelsmay be up to about 0.25 inch thick, or in some examples, may have athickness of up to about 0.5 inches. Other thicknesses may be used. Thepanels, and depending on the materials selected, may have a differentthickness, and the examples described herein are provided forillustration purposes and are not to be taken in a limiting sense.Generally, any foam or other semi-rigid material may be used to providea desired level of rigidity while being sufficiently lightweight forself-deployment. Generally, the panels may be made from any materialthat is sufficiently stiff or rigid to maintain their shape in thedeployed state.

Referring back to FIG. 1, in some examples, the apparatus may include apair of base panels 116A-B (also referred to as back cover panels),which may lie generally parallel to the door 12A-B of the truck. Thebase panels 116A-B may be in direct contact with the door 12A-B, or insome examples, the base panels 116A-B may be spaced apart from thesurface of the door, as will be further described, e.g., to provideclearance for operation of the cam lock bar of the truck door. Moreover,the base panels 116A-B may be hingedly attached to the door, forexample, using a double-hinge mechanism (not shown in FIG. 1) as will bedescribed with reference to FIGS. 5-6. The double-hinge mechanism mayfacilitate lateral movement of the base panels 116A-B during opening andclosing of the door 12A-B, e.g. to avoid trapping or pinching the basepanels 116A-B at the door hinge bite. As will be understood, the truckdoor 12A-B may swing approximately 270 degrees. Because the base panels116A-B may extend all the way to the edge of the door (e.g., to the doorhinges), it may be desirable for the base panels 116A-B to be movabletowards centerline (e.g., edges of the doors opposite the door hinges)when the door 12A-B rotates to the about 270 degree position. Moving thebase panels 116A-B towards centerline may prevent the apparatus 100 frombecoming pinched at the door hinge bite. The double-hinge mechanism maybe biased so that it automatically returns to the neutral position withthe driver-side/curb-side edges of the apparatus 100 generally alignedwith the driver-side/curb-side edges of the door 12A-B when the door12A-B is pivoted back to about 90 degrees. Attachment of the apparatus100 to the door 12A-B using double-hinge mechanisms of the kinddescribed herein may facilitate in some examples shifting of the wholeapparatus 100 (e.g., each half of the apparatus 100) towards centerlineto allow full compaction of the apparatus 100 against the side of thetrailer 10 and forward out of the door hinge bite. Accordingly, examplesof drag reduction apparatuses described herein may allow for easieropening and closing of the doors of the land vehicles to which theapparatuses are attached.

The peripheral panels (e.g., the top 102A-B, bottom 112A-B, and sidepanels 106A-B) may be pivotally or hingedly attached to the base panels116A-B along a perimeter of the cavity 120 that forms when the panelsare deployed. In some examples, the bottom panels 112A-B may be attachedalong a bottom edge of the apparatus 100. In other examples, e.g., asshown in FIG. 1, the bottom panels 112A-B may be attached at anintermediate location along the vertical axis. For example, the bottompanels 112A-B may be located midway or slightly below the midpointbetween the top panels 102A-B and the bottom of the doors 12A-B. Theapparatus may include any number of retention mechanisms 114, which maybe configured to limit the movement of some of the panels, e.g., theamount of rotation of any of the peripheral panels relative to the basepanels 116A-B. For example, one or more strings, cords, bungees, orother suitable tension members may be attached between the base panels116A-B and any one of the top 102A-B, bottom 112A-B, and/or side panels106A-B. One or more retention mechanisms 114 according to the examplesherein may be attached to any of the peripheral panels. Optionally,retention mechanisms 114 may be coupled to the bottom panels 112A-B soas to prevent the bottom panel 112A-B from folding upward when deployed,e.g., due to low pressure. One or more retention mechanisms 114 may beincluded for the side 106A-B and/or top panels 112A-B. The retentionmechanism 114 (e.g., cord) may be collapsible to allow a peripheralpanel to fold towards the base panels 116A-B. The retention mechanism114 may have a fixed length when expanded to prevent the peripheralpanel from rotating beyond a predetermined position (e.g., up to 90degrees) relative to the base panels 116A-B.

In some examples, an over-center brace member 110A-B, which may be madeof metal or a rigid plastic material, may be used. As shown in FIG. 1, apair of over-center braces 110A-B may each be attached to an outersurface of one of the base panels 116A-B and to a bottom surface of eachof the top panels 102A-B facing the respective base panel 116A-B. Theover-center brace member 110A-B may be self-deployable in that it may beconfigured to expand due to the lifting force on the panel. An exampleof an over-center brace member 110 according to an embodiment of thedisclosure is shown in more detail in FIG. 4. The brace may include anover-center mechanism 415 which urges the over-center brace member 110into an expanded position once deployed, which may be advantageous inpreventing premature collapse of the top panel 102A-B. One or moreover-center braces 110A-B may be included between any of the peripheralpanels and the base panels 116A-B. In some embodiments, the over-centerbrace 110A-B may be configured for providing any of the peripheralpanels in up to about 45 degree position relative to the base panels116A-B, which may restrict hyper-extension of the panels and may be anaerodynamically desirable position.

Foldable joints, which may also be referred to as hinge joints or livinghinges, may be disposed between each panel to allow the panels to pivotrelative to one another. The foldable joints may be implementedaccording to any suitable technique. For example, the foldable joint mayinclude one or more layers of flexible material which is secured (e.g.,fused, heat welded, mechanically fastened, etc.) along respective edgeportions of adjoining or adjacent panels. The foldable joint may beconfigured to reduce or minimize resistance to pivotal motion of thepanels. In some instances, the foldable joint may be biased so as tourge or facilitate pivotal motion in one direction and/or resistrotation in an opposite direction. The foldable joint may be amulti-layer structure (e.g., a two-ply structure) made from elastomericor other durable flexible materials. In some examples, living hinges maybe implemented using mechanically fixed dual durometer extrusions. A gapmay remain between the layers of the foldable joint for flex and minimalresistance to the pivoting/folding action.

The foldable joints may be located between the transition panels 104A-B,108A-B and the side panels 106A-B, the top panels 102A-B, and the bottompanels 112A-B. The foldable joints may also be between side panels106A-B and the base panels 116A-B, the top panels 102A-B and the basepanels 116A-B, and the bottom panels 112A-B and the base panels 116A-B.The foldable joints may be located at edges of two or more panels. Forexample, driver-side side panel 106A may have edges 160, 162, 164, and166. Adjacent transition panel 104A may have edges 140, 142, and 144. Afoldable joint 170 may be located at the interface of edge 160 of sidepanel 106A and edge 140 of transition panel 104A. A joint similar tofoldable joint 170 may be located along an edge transition panel 104Aand an edge of top panel 102A. A similar foldable joint similar to thefoldable joint 170 may be located along an edge of transition panel 108Aand an edge of bottom panel 112A. Transition panel 108A may have asecond foldable joint along a second edge adjacent to a back surface ofside panel 106A. However, other attachment mechanisms between transitionpanel 108A and the back surface of side panel 106A may be used. Similarfoldable joints may also be located along corresponding panels on thecurb-side panels (B).

Side panel 106A may have a foldable joint 172 along edge 166 to couplethe side panel 106A to an outer edge the base panel 116A. Side panel106A may also be hingedly coupled to the outer edge of the base panel116A. In an alternative embodiment, the side panel 106A may be directlycoupled to an edge of the door 12A along edge 166. Similarly, top panel102A may have a foldable joint along a top edge of the top panel and atop edge of the base panel 116A to couple the top panel 102A to the basepanel 116A. Top panel 102A may also be hingedly coupled to the top edgeof the base panel 116A. In an alternative embodiment, the top panel 102Amay be directly coupled to a top edge of the door 12A. Similar foldablejoints or other attachment mechanisms may also be located alongcorresponding panels on the curb-side panels (B).

As shown in FIG. 3, the apparatus 100 may remain attached to the trailer10 door 12B, when opening and/or closing the door 12B, including whilemoving the handle 14B of the cam lock bar 16B and/or stowing the door12B in a secured open position. In some examples, the apparatus 100 mayspan most or substantially all of the surface area of the cargo door 12.The apparatus 100 may be generally rectangular in plan and may beshaped/sized such that it covers most or all of the surface area of therear end of the truck trailer 10. The apparatus 100 may be provided insome examples with a cutout or indented portion along a bottom portionof the apparatus 100 such that the apparatus, when attached at the backof the truck trailer 10, remains clear of the handle 14 of the cam lockbar 16.

In some examples, the drag reduction apparatus 100 may be affixed to theback end of a land vehicle (e.g., a truck) in a manner which does notinterfere with operation of the cargo door of the truck. For example,the drag reduction apparatus 100 may be attached directly to the cargodoor and may have a shape which allows for the door 12 to be operated(e.g., opened or closed) without removing the apparatus 100 or withouthaving to first manipulate the apparatus 100 (e.g., move the apparatusaside or out of the way) in order to access and/or open the cargo door12. For example, as previously described, the apparatus 100 may beattached to the door 12 using a double-hinge mechanism so as to preventinterference of the panels with operation of the cam lock bar 16 and/orprevent the panels from becoming pinched and/or damaged by the doorhinge bite. Each base panel 116 may extend between the edge of the door12 (e.g., proximate the door hinges at the driver-side and curb-sideedges) and about the midpoint or centerline of the rear end of thevehicle trailer 10, where the two doors meet. As will be understood, theapparatus 100 may include two separate portions, left or driver-sideportion and right or curb-side portion, and each portion may be securedto each of the door panels 12A-B of a split-type cargo door. In thismanner, each of the two portions of the apparatus 100 may remainattached to each door panel 12A-B while the door is opened and closed(see e.g., FIG. 3).

The left and right portions of the apparatus 100 may adjoin and/oroverlap at a seam 118 corresponding to the seam or interface of the twocargo doors 12A-B. The two portions may be configured to engage at theseam 118, e.g., to offer a nominal resistance to separation of the twoportions during use. As described, the top panel section includes a left102A and right 102B top panel sections. Aerodynamic advantage (e.g. dragreduction) may be diminished if only one of the left and right panelsdeploys. Thus, it may be advantageous for the left 102A and right 102Btop panel sections to remain attached and/or deploy simultaneously.Similar advantages may be achieved by facilitating simultaneousdeployment of the bottom left 112A and bottom right 112B panel sections.A mechanism may be provided at the seam 118, e.g., along any portions ofthe edges which overlap, which may resist separation of the panels alongthe seam. For example, magnetic or mechanical engagement mechanisms maybe used. Magnetic tape or a plurality of magnetic strips may be providedalong at least a portion of the seam for engagement between the twoportions. Other magnet shapes may also be used. An example of a magnetplaced on the seam 118 of the top panels 102A-B is shown in FIG. 4. Inthis example, the magnet 420 is attached to the edge of the right toppanel 102B. The magnet 420 extends beyond the edge of the right toppanel 102B to engage with the left top panel 102A. In other examples,mechanical attachment (e.g., Velcro) or adhesives (e.g., removable,reusable, pressure-sensitive adhesives) may additionally or instead beused. Other suitable attachment techniques may also be used.

An overlap at the seam 118 may facilitate an engagement between the twoportions of the apparatus 100. Furthermore, in some embodiments,additional mechanisms for maintaining a connection between the twoportions of the apparatus may be provided. In some examples, the panelsmay be configured such that they over-lap with curb-side panels over thedriver-side panels. In some embodiments, this can be achieved by sizingthe curb-side panels (B) wider than the driver-side panels (A) along thehorizontal or lateral dimension. In other examples, and for ease ofmanufacture, each of the two halves may be generally the samesize/dimensions, and separate strips of material may be attached alongoverlapping edges at the curb-side or driver-side portion as may bedesired. A wider curb-side portion may be advantageous in many cases,e.g., as standard truck doors typically use an open/close arrangement inwhich the curbside door 12B closes over the driver side door 12A. Thus,in a standard configuration, a curb-side door 12B may typically first bedisengaged first prior to opening the driver side door 12A. Acorresponding overlap of the panels may be used.

One or more double-hinge mechanism according to the present examples maybe used at the back (or unexposed) surface of the base panels 116A-B toattach the apparatus 100 to the cargo door 12A-B of the truck. Thedouble-hinge mechanisms may be connected between the door panel 12 and afacing surface of the base panel 116. FIGS. 5A-B and FIGS. 6A-Cillustrate examples of double-hinge mechanisms described herein. Adouble-hinge mechanism may be configured to allow the base panels 116A-Bof the apparatus to move laterally relative to the door panels 12A-B,for example up/down or side-to-side, depending on the orientation of thedouble-hinge mechanism. For example, one or more double-hinge mechanismsmay be disposed along the horizontal direction for translating thepanels side to side, e.g., as described above for avoiding the bite ofthe door. The double-hinge mechanisms may be advantageously configuredto allow the apparatus to temporarily move away or be provided in aspaced apart position from the door when the cam lock is operated. Asmay be appreciated, during locking and unlocking of the door, the camlock bar 16 of the door 12 may displace outward from the door. Thismotion of the cam lock bar 16 would be obstructed by any structure thatis rigidly mounted across the bar. Advantageously, the base panels116A-B of the apparatus 100, which cover the cam lock bar 16, may bemounted in a movable manner using the double-hinge mechanism which mayallow the panels to displace outward similar to the cam lock bar 16 andmay further allow the panels to subsequently return to their neutralposition closer to the door panels. In other examples, as may be neededor desired, the double-hinge mechanisms may be arranged vertically fortranslating the panels up and down, e.g., in examples in which thepanels are sized smaller than the doors and/or up/down movement mayinstead be desired.

In the illustrations in FIGS. 5A-B, a first horizontal member 505 mayrepresent the door panel and a second generally parallel horizontalmember 510 may represent the base panel of the apparatus 100. The twohorizontal members 505, 510 may be attached using a double-hingemechanism 500 which may be represented by the two connecting members515A-B that extend between the first 505 and second 510 horizontalmembers. The double-hinge mechanism 500 may include two pivotalconnections 520A-B, 525A-B, each to one of the two horizontal members505, 510, with one of the pivotal connections 520A-B, 525A-B pivoting inone direction and the other pivoting in the opposite direction. Thedouble-hinge mechanism 515 may be configured to rotate or pivot up to180 degrees at each of the two pivotal connections. This may enable thehorizontal member 510 representing the apparatus portion to move awayfrom and sideways relative to the door panel (e.g., from a firstposition as shown in FIG. 5A to a second position in FIG. 5B). As willbe appreciated, during the position shown in FIG. 5B, the horizontalmembers 505, 510 may be sufficiently spaced apart to allow for movementof another structure which may be disposed between the two verticalpanels. A bar 535 coupled to the first or second horizontal member 505,510, may be used to operate the double-hinge mechanism. In someembodiments, when rotated, the bar 535 may cause the horizontal membersto move from the position shown in FIG. 5A to the position shown in FIG.5B. The bar 535 may be coupled by a strap, clamp, or other suitableattachment mechanism. In one embodiment, the bar 535 may be cam bar 16.Cam bar 16 may be rotated by a user operating the handle 14. A stop 530may be provided to the double-hinge mechanism 500 to limit the movementof the double-hinge mechanism 500, e.g., to prevent either fullyexpanding or fully collapsing the double-hinge joint, as may be desired.Each pivotal connection 520A-B, 525A-B may be implemented using anysuitable pivotal joint, for example a conventional hinge or aspring-loaded hinge which may enable an over-center action to urge themovement of the hinge in a predetermined direction. The two pivotaljoints may be connected using a connecting member which may be made froma rigid material, such as metal, composite, or other suitable materials.

Referring to FIGS. 6A-6C, an example of a double-hinge joint 600 isdepicted, which includes a first pivotal joint 605 connected to a firstpanel 610 (e.g., bottom plate) and a second pivotal joint 615 connectedto a second panel 620 (e.g., top plate). The first and second pivotaljoints 605, 615 are connected to each other using a connecting member625. In some embodiments, the connecting member may be a metal plate.The first and second pivotal joints 605, 615 may be dissimilar, forexample the first pivotal joint 605 may be an over-center joint (e.g., aspring loaded hinge joint), while the second pivotal 615 joint mayfreely rotate up to about 180 degrees. Using an over-center joint forone or more of the pivotal joints of the double-hinge member 600 may beadvantageous as it may help retain the double-hinge member 600 in afirst, e.g., neutral or collapsed position, as shown in FIG. 6A, or asecond, e.g., expanded position, as shown in FIG. 6C, resisting atransition between the two positions, as shown in FIG. 6B. This may beuseful for reducing or minimizing the risk that the panels willunexpectedly push away from the door, e.g., during use/deployment of theapparatus.

Apparatuses according to the present disclosure may be configured to beself-deploying, in that the panels may automatically unfold when a speedof the land vehicle reaches or exceeds a threshold speed high enough togenerate a low pressure region around the vehicle (e.g., in the wake ofthe vehicle). The pressure around the vehicle may decrease as the speedof the vehicle increases resulting in high/low pressure regions, withthe high pressure region located immediately behind the vehicle and thelow pressure regions located around and/or in the wake of the vehicle.Thus, as the vehicle speed increases, a suction or outward/lifting forcemay be produced around and/or in the vehicle's wake, which may cause thepanels of the apparatus to automatically deploy or unfold to form acavity (see FIG. 1). As the speed of vehicle increases, the outermost ofthe peripheral panels may be pulled outward due to the low pressureregion around the vehicle and as these panel unfold, the remainingpanels (e.g., panels sandwiched between the outermost and base panels)may be pulled outward in part by the pressure differential and furtherassisted by the foldable attachment of the panels (e.g., by virtue ofthe transition panels connecting the main panels). The panels may remainin their unfolded or partially unfolded configuration as long as a lowpressure region remains at the back of the vehicle. The panels mayreturn to the folded configuration when the speed of the vehicle isbelow the threshold speed and the low pressure region diminishes. One ormore of the panels may return to their folded position due, in part, togravity. For example, when the speed of the truck is insufficient tomaintain the cavity in its expanded shape, gravity may act on the toppanel pulling it down and thereby causing the side panels to foldinwards. In some examples, the panels may be manually expanded prior todeparture or folded down after reaching its destination by the vehicleoperator, e.g., when the operator may wish to access the cargocompartment by opening the rear door on which the drag reducingapparatus is mounted. In some examples, the sizes, weights, compositionand folding configuration of the panels may be further tailored tofacilitate lower resistance in opening and folding of the drag reducingapparatus.

In some examples, drag reduction apparatuses according to the presentdisclosure may further be used as a gap-fill when multiple land vehicles(e.g. trailers) are arranged to travel in a coordinated manner (e.g. aroad train configuration). In examples, two or more trailers may bepulled simultaneously using the same tractor unit, in which case, dragreduction apparatuses as described may be mounted at the rear end ofeach trailer. That is, one or more drag reduction devices are providedat intermediate locations along the length of the road train. Inaddition to providing drag reducing as a gap-fill apparatus, thisarrangement may offer the added advantage of obviating the need formoving the drag reduction apparatus from one trailer to the next,particularly when the trailers are used interchangeably in a double- ortriple-trailer configuration in which the trailers may be switched foreand aft.

While an exemplary folding configuration is depicted in the exemplaryapparatus in FIGS. 2-3, other folding patterns, for example, in whichthe side panels overlap the top and/or bottom panels may be used. Insome examples, and depending on the desired configuration, differentshapes and fold lines may be used to effectuate different expandedconfigurations, for example configurations resulting in a more conicalstructure or various non-symmetric structures.

In some examples, when the operator desires to access the cargocompartment of the vehicle, the operator may operate the cam lock bar ofthe cargo door (see FIG. 3) and may open and close each door with thepanels remaining attached thereto. The left and right portions of theapparatus are attached such that they move with the door panel. In otherwords, and contrary to known devices for drag reduction, the operatordoes not need to independently move the apparatus out of the way beforeopening the door using examples of drag reduction devices describedherein but instead, the apparatus may move with the door and remaingenerally flat against the door during opening and closing of the door.If desired, additional straps, bungees, or other attachment mechanismsmay be provided for securing the panels in the folded position.

While various aspects and examples have been disclosed herein, otheraspects and examples will be apparent to those skilled in the art. Thevarious aspects and examples disclosed herein are for purposes ofillustration and are not intended to be limiting. Thus, the presentdisclosure is not intended to be limited to the embodiments shown hereinbut is to be accorded the widest scope possible consistent with theprinciples and novel features as defined by the following claims.

1. An apparatus, comprising: a plurality of panels including a pair oftop panels, a pair of bottom panels, first and second side panels, and aplurality of transition panels connecting the top, bottom, and sidepanels, the plurality of panels foldably coupled to allow the panels tobe provided between a folded configuration in which the panels are flatagainst each other and a deployed configuration in which the panelsdefine a cavity therebetween, wherein the pair of top panels areconfigured to transition between the folded configuration and thedeployed configuration simultaneously and the pair of bottom panels areconfigured to transition between the folded configuration and thedeployed configuration simultaneously; and a pair of base panels,wherein the pair of top panels and the first and second side panels arepivotally coupled to the base panels; and a plurality of hingemechanisms attached to the base panels for coupling the base panels tofirst and second doors of a land vehicle.
 2. The apparatus of claim 1,further comprising a retention mechanism configured to limit movement ofone or more of the panels.
 3. (canceled)
 4. The apparatus of claim 1,wherein the pair of top panels and the first and second side panels arehingedly coupled to the pair of base panels around a perimeter of thecavity, and the bottom panels are hingedly coupled to the pair of basepanels midway along a length of the base panels, wherein the panels areflat against each other against a front surface of the base panels inthe folded configuration.
 5. (canceled)
 6. The apparatus of claim 1,wherein each of the hinge mechanisms comprises a double-hinge mechanismwhich includes two pivotal connections configured to pivot in oppositedirections.
 7. The apparatus of claim 6, wherein the pivotal connectionsof the double-hinge mechanism are configured to pivot up to 180 degrees.8-9. (canceled)
 10. The apparatus of claim 1, wherein one of the basepanels is attached to one of first and second doors and the other one ofthe base panels is attached to the other one of the first and seconddoors such that any of the first and second doors can open while each ofthe base panels remains attached to a respective one of the doors. 11.The apparatus of claim 1, wherein one of the top panels is longer thanand overlaps the other top panel, and one of the bottom panels is longerthan and overlaps the other bottom panel.
 12. The apparatus of claim 1,wherein the top panels are magnetically coupled to one another and thebottom panels are magnetically coupled to one another. 13-17. (canceled)18. The system of claim 1, wherein the plurality of panels areconfigured to automatically transition to the deployed configurationwhen the land vehicle moves at a threshold velocity.
 19. The system ofclaim 1, wherein the plurality of panels are configured to automaticallytransition to the folded configuration when the land vehicle moves belowa threshold velocity.
 20. The system of claim 1, wherein the pluralityof panels comprise a rigid material, the rigid material configured toprevent the plurality of panels from sagging in the deployedconfiguration.
 21. The apparatus of claim 2, wherein the retentionmechanism comprises one or more cords, over-the-center brace members, orcombinations thereof.
 22. The apparatus of claim 1, wherein the panelsare folded according a folding configuration in which the top panels arefolded on top of the side panels in the folded configuration.
 23. Theapparatus of claim 1, wherein the hinge mechanisms facilitate lateralmovement of the base panels during opening and closing of a door of theland vehicle.
 24. The apparatus of claim 1, wherein the hinge mechanismsare biased so that the hinge mechanisms automatically return to aneutral position when the doors are pivoted back to about 90 degrees.